Double rod curtains consist of two narrow bars curtain, in front of the other. The small size makes them better bars to support lightweight curtains in the smaller rod and a border on top of the curtains. Curtains hang aims closed because no creases as curtains. No folds that requires great effort to restore the curtains after opening or closing them for hanging carefully. That is why the curtains are best for a double bar. The bar does not have the pulley system of a scroll bar because the curtains hanging from the double bar are meant to be left closed or manually pulled aside and held with clamps. If you have light shades and no plans to open them very often, you can use a double bar, but not the best hardware for the job.
You will need a crossbar to support the weight of the double rod curtains and provide a way to open and close. Hang curtains hooks scroll bar. The hooks allow the curtains glide smoothly along the track when it opens and closes. Place a second rod, slightly longer in front of the traverse rod valance. Valance should extend beyond the ends of the curtain and in the corners of the bar to the wall.